1. Field of the Invention
This invention generally relates to an optical system and, more particularly, to an optical system for detecting click events and a click detection method therefor.
2. Description of the Related Art
To date, the optical mouse has become a necessary peripheral device of personal computer systems such that a user may execute a specific function, such as cursor control, single click or double click on an icon, by using the mouse. However, to a portable electronic device such as a laptop computer or a personal digital assistance (PDA), a mouse connected externally is inconvenient to use.
Therefore, the field provided an optical mouse which is directly installed on the portable electronic device such that a user does not need to carry an external mouse with him or her thereby increasing the convenience of portable electronic devices.
For example U.S. Pat. No. 7,313,255 provides a click event detection system that sequentially detects a lift-up motion and a put-down motion, and identifies whether a time different between a lift-up time and a put-down time is within a predetermined time limit to accomplish the detection of a click event.
Please refer to FIG. 1A, it shows a flow chart of detecting a click motion of the conventional detection system, wherein the click motion may be a lift-up motion or a put-down motion. Please refer to FIG. 1B, it shows a flow chart of detecting a click event of the conventional detection system, wherein a lift-up time is checked when a lift-up motion is detected and then the detection system continuously detects another click motion until a put-down motion is detected and a put-down time will be checked at the same time. When a time difference between the lift-up time and the put-down time is within a predetermined time limit, a click event is identified.
However, the conventional detection system described above has at least the following problems: (1) the mechanism of identifying a click event by detecting a lift-up motion followed by a put-down motion sequentially does not fully match the instinct of human race; (2) a put-down motion might be detected long after the occurrence of a lift-up motion but the detection system will continuously identify whether a put-down motion is occurred thereby wasting system resources.
Accordingly, the present invention further provides an optical system and a click detection method therefor that may identify a single click, a double click and even a multiple click event.